docs: media: dvb: enable warnings for most headers

docs: media: dvb: enable warnings for most headers

Except for two exception rules and dmx.h, the other files
are already handling properly cross references.

Fix the two exception rules for frontend.h, as those are
false-positives:

	include/uapi/linux/dvb/frontend.h:959: WARNING: can't link to: c:type:: FE_GET_PROPERTY
	include/uapi/linux/dvb/frontend.h:933: WARNING: can't link to: c:func:: FE_SET_FRONTEND_TUNE_MODE

The dmx.h are actual issues that will require an extra
patch to fill gaps.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Message-ID: <9ae6556ebd47de4f066a149ab0bbe7ce27acf2c4.1759329363.git.mchehab+huawei@kernel.org>